New types of memory have demonstrated significant potential to compete with commonly utilized types of memory. For example, non-volatile spin-transfer torque random access memory (referred to herein as “STRAM”) and resistive random access memory (referred to herein as “RRAM”) are both considered good candidates for the next generation of memory.
In order to reverse a STRAM cell, the spin torque from the writing current has to overcome the in-plane anisotropy (which is equal to 2πMs, where Ms is the saturation magnetization). The in-plane anisotropic field is about 5000 Oersted (Oe) for a nickel iron (NiFe) layer. The thermal stability and retention characteristics of such a cell is provided by the uni-axial anisotropic field, which is only around 500 Oe. A memory cell that reduces the in-plane anisotropic field, thereby affording a cell that is easier to switch, but increases the uni-axial anisotropic field, thereby affording a cell that is more thermally stable and retains the state written to it.